Audio Cable & Connector Reference
Choosing the right cable and connector is essential for clean audio. This reference covers all the common audio connector types, whether they carry balanced or unbalanced signals, their pin configurations, and practical maximum cable lengths before signal degradation becomes noticeable.
Connector Types at a Glance
| Connector | Pins / contacts | Signal type | Max. length | Common use |
|---|---|---|---|---|
| XLR (3-pin) | 3 (pin 1: ground, 2: hot, 3: cold) | Balanced | ~100 m | Microphones, line-level connections, stage runs |
| TRS (6.35 mm / ¼″) | 3 (tip: hot, ring: cold, sleeve: ground) | Balanced or stereo | ~25 m (balanced) | Studio monitors, headphones, insert points |
| TS (6.35 mm / ¼″) | 2 (tip: signal, sleeve: ground) | Unbalanced | ~6 m | Guitar leads, instrument cables |
| TRS (3.5 mm / ⅛″) | 3 (tip: left, ring: right, sleeve: ground) | Unbalanced stereo | ~2–3 m | Headphones, aux connections, portable devices |
| RCA (phono) | 2 (centre pin: signal, outer ring: ground) | Unbalanced | ~5–6 m | Hi-fi, DJ mixers, turntables, consumer audio |
| Speakon (NL2/NL4) | 2 or 4 (1+/1−, 2+/2−) | Speaker-level | ~30 m | PA speakers, powered monitors, subwoofers |
| MIDI (5-pin DIN) | 5 (pins 4 & 5: data, pin 2: shield) | Digital data | ~15 m | Keyboards, drum machines, sequencers |
| USB-A / USB-B | 4 (power, D+, D−, ground) | Digital audio | ~5 m (USB 2.0) | Audio interfaces, MIDI controllers, microphones |
| USB-C | 24 | Digital audio | ~4 m (USB 3.2) | Modern audio interfaces, mobile recording |
| Optical (TOSLINK) | Fibre optic | Digital (S/PDIF) | ~10 m | Hi-fi connections, surround sound, DACs |
Balanced vs Unbalanced
The key difference between balanced and unbalanced connections is noise rejection. Balanced cables carry two copies of the signal with opposite polarity, so any interference picked up along the cable is cancelled out at the receiving end. This is why XLR and balanced TRS cables can run much longer distances without degradation.
| Feature | Balanced | Unbalanced |
|---|---|---|
| Conductors | 3 (hot, cold, ground) | 2 (signal, ground) |
| Noise rejection | Excellent (common-mode rejection) | Poor — susceptible to interference |
| Practical max. length | 25–100+ metres | 3–6 metres |
| Connectors | XLR, TRS | TS, RCA, 3.5 mm TRS (stereo) |
| Typical use | Professional studio & stage | Instruments, consumer gear, short runs |
Cable & Connection Calculators
Use our free tools to plan your cable requirements:
- Cable Length Calculator — work out cable runs for your setup
- Signal Loss Calculator — estimate signal degradation over distance
Maximum cable lengths are practical guidelines and depend on cable quality, shielding, and the electromagnetic environment. High-quality cables with good shielding may exceed these distances; cheap cables may fall short.